Be the first to like this
In conventional heat treatments or rolling schedules, the microstructure can be properly identified by its mean attributes. These parameters can properly predict the ductile-brittle (DB) transition temperatures measured by Charpy tests. However, if the austenite grain size distribution prior to transformation remains heterogeneous, after transformation, wider distributions of grain sizes will be obtained. In this context, the classical approaches do not properly predict the DB regime. This study analyzes the behavior of several ferrite-pearlite microstructures with different local heterogeneities. Grain size distributions, EBSD analysis identifying high angle misorientation boundaries and cleavage facet measurements were performed. These parameters have been incorporated in previous empirical expressions in order to quantify the contribution of these heterogeneities to the DB transition temperature.